Vincity — A Mini Study | Carolina Redesign

Vincity.
A measurement, a metaphor, a math.

How often a street network crosses itself determines almost everything about whether a neighborhood will be valuable, walkable, financially solvent, or none of the above. The math is simple. The implications are not.

By Jimmy Ardis · Carolina Redesign · A companion piece to the Urban Productivity series

A small number with large consequences

Most people walk through a city without noticing how often they pass through intersections. They notice traffic, they notice storefronts, they notice whether the place "feels like something." What they don't realize is that the thing they're responding to has a number attached to it.

That number is vincity: the count of thoroughfare intersections per acre of land. It sounds technical because it is, but the underlying intuition is simple. A neighborhood with many intersections per acre has a finely-woven street network — small blocks, frequent corners, many possible routes between any two points. A neighborhood with few intersections per acre has a coarse network — long blocks, few connections, forced routes through a small number of arterials.

The first kind of network tends to produce buildings, sidewalks, storefronts, and corner shops. The second kind tends to produce parking lots, strip plazas, and traffic lights. Both kinds get called "neighborhoods." Only one of them tends to pay its way in property tax.

Two grocery stores, same product mix.

Imagine the same square footage, the same inventory, the same number of shoppers. The only difference is the floor plan. Look at what changes — and ask yourself which one wants to be in business next year.

The actual co-op · East Aurora, NY

Fine grain. Five aisles. Every section reachable from every other section.

East Aurora Co-op Market floor plan showing five short aisles between perimeter departments (Produce, Dairy, Frozen, Beer, Seafood & Meat, Bakery), with multiple cross-aisles connecting them.

Five short aisles. Perimeter departments — Produce, Dairy, Frozen, Beer, Seafood & Meat, Bakery — wrap a fine interior grid. A shopper headed for bread passes Cheese and Hot Soups and a Café on the way. A shopper headed for produce passes Bulk Coffee, Dried Fruit, Hot Meals to Go. Every aisle intersects every department. The store rewards browsing and produces impulse purchases. Cross-traffic between sections is the design.

5 aisles

8+ departments touched

≈ high vincity (per cart-trip)

Hypothetical · Designed by a traffic engineer

One arterial. Six cul-de-sacs. Each department a dead end.

Satirical architectural plat drawing of a hypothetical grocery store designed by a traffic engineer: one 'Main Arterial' aisle with six perpendicular cul-de-sacs labeled Dairy Cul-de-Sac, Produce Court, Frozen Place, Bakery Turnaround, Meat Terminus, Dry Goods Dead End, each terminating in a circular turnaround.

One central spine — the "Main Arterial." Six perpendicular aisles dead-end into circular turnarounds: Dairy Cul-de-Sac, Produce Court, Frozen Place, Bakery Turnaround, Meat Terminus, Dry Goods Dead End. A shopper headed for bread enters through Parking Required, drives the Main Arterial, takes the Bakery exit, hits the turnaround, returns to the Arterial. Cross-traffic between Dairy and Bakery requires backing all the way out of one cul-de-sac and into another. Browsing is impossible. Impulse purchases collapse. The store rewards lists, in and out.

1 arterial

1 department per trip

≈ low vincity (per cart-trip)

"The same principle that makes the co-op floor plan work — and that makes the cul-de-sac version absurd — is the principle that makes neighborhoods either pay their way or quietly cost their cities money. The plat is the product."

The vincity of our case studies

Across the patterns documented in this series, the vincity values track exactly the per-acre productivity values reported in the parcel data. Here is the score, smallest to largest:

0.23

Savannah Hwy

West Ashley auto strip
post-1950

0.39

Elliotborough

Eastern half of CENA
mid-19th century

0.50

Strong Towns min

Marohn / Urban3
fiscal threshold

0.61

Walled City

Charleston, 1704
incl. alleys

1.83

Savannah, GA

Oglethorpe wards, 1733
designed for connectivity

Read the row from left to right. The auto strip is well below the Strong Towns minimum. Elliotborough — a 19th-century working-class extension of the historic peninsula — sits just below the threshold. The walled city, woven over a century with its dense alley network, comfortably exceeds it. Savannah, Georgia — purpose-built for connectivity by James Oglethorpe in 1733 — is more than three times the recommended minimum and remains, three centuries later, one of the most economically valuable acres in the American South.

Vincity is not a measure of taste. It is a measure of how the network was designed — and what kind of value the network can hold.

Why it tracks value

The correlation between vincity and per-acre property tax revenue is too tight to be accidental. The mechanisms by which they're related, however, are worth naming explicitly — because each one is a separate lever a city has to pull.

Frontage economics

More intersections mean more corner lots. Corner lots are the most valuable retail real estate in any walkable district because two streets of pedestrian traffic feed each storefront. High vincity multiplies that effect.

Block geometry

Small blocks force taller, deeper, more efficient buildings. A 600-foot suburban block accommodates strip-mall buildings with parking out front. A 200-foot historic block forces a four-story mixed-use building wall to wall. The smaller block produces more building per acre.

Route diversity

More intersections mean more ways to get from A to B. Pedestrians, cyclists, and emergency vehicles all benefit. Traffic distributes across many small streets instead of concentrating on a few large arterials. The neighborhood becomes more walkable and less stressful — both of which are priced into property values.

Social capital

Jane Jacobs's original point. Frequent intersections mean frequent chance encounters, mixed uses, "eyes on the street." Higher vincity produces more of what Jacobs called the intricate sidewalk ballet — the social texture that turns proximity into community. That texture has economic consequences, even if they don't fit on a balance sheet.

The Elliotborough question

The numbers above raise an obvious question. Elliotborough sits at 0.39 — below the Strong Towns minimum of 0.50 — and yet the parcel data show it generating $149,000 per acre per year in property tax. That's more than 24 times what the Savannah Highway strip produces. How does a sub-threshold vincity neighborhood pay its way that well?

Three contributing factors. First, Elliotborough sits adjacent to and shares infrastructure with the walled city — its residents can walk to a network well above the threshold. Second, the missing intersections are predominantly missing alleys; Vince Graham's manual count of historic Charleston's alley network suggests a similar mid-19th-century alley density that has been lost to OSM mapping or to physical erasure. Third, the Upper King Street corridor concentrates commercial value into a narrow band; the rest of the neighborhood can be slightly coarser without sacrificing the overall fiscal output.

The interesting implication: if Elliotborough's vincity were brought back up to the walled city's 0.61 — by reactivating lost alleys, formalizing existing service ways, or breaking up a few of the longest blocks — the productivity multiplier could compound. Even small block-scale interventions reliably increase per-acre value. The neighborhood's structural weakness is also its structural opportunity.

The 0.5 rule, and why it matters.

Chuck Marohn and Joe Minicozzi have documented per-acre productivity across hundreds of American cities. The pattern they keep finding: when intersection density falls below roughly 0.5 per acre, the development pattern becomes a net fiscal drain on its city — even when the buildings on it look prosperous. Maintenance costs scale with road miles. Service costs scale with parcel counts. Revenue scales with land value, which scales with vincity.

0.50 intersections per acre
The Strong Towns recommendation. Below this, the math turns negative. Above this, growth can pay for the infrastructure that supports it.

This is not a stylistic argument. It is an arithmetic one. The number says nothing about how a neighborhood should look — only about whether the way it is built can fund the services it requires. Two centuries after the walled city was woven, and three centuries after Oglethorpe surveyed Savannah, both of those neighborhoods can still afford themselves. Most things built since are still relying on subsidies from the patterns that came before.

Vincity.
A measurement, a metaphor, a math.